Process for producing crimped yarns



YUTAKA MAEDA ETAL 3,434,277

PROCESS FOR PRODUCING CRIMPED YARNS March 25, I969 Sheet Filed June. 11. 1965 FIG.

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PROCESS FOR PRODUCING CRIMPED YARNS Sheet a of 4 Filed June 11. 1965 FIG. 2

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PROCESS FOR PRODUCING CRIMPED YARNS Filed June 11 1965 Sheet 3 of 4 M/I/A'A/TO'GSJ max/-44 M4554 KAO/VL/ H4604 7.4750544 MAI/M070 72751/0 KAS/l/WAG/ run/#20 H404 4/4640 GOM/ A front;

March 25, 1969 YUTAKA MAEDA ETAL PROCESS FOR PRODUCING CRIMPED YARNS Filed June 11. 1965 Fineness Sheet 4 of 4 FIG.4

A rroxws the Yarn United States Patent 3,434,277 PROCESS FOR PRODUCING CRIMPED YARNS Yutaka Maeda, Kaoru Maeda, Tetsuya Yamarnoto, Tetsuo Kashiwagi, Yukihiro Hada, Tokue Kato, and Nagao Gomi, Yamanashi-ken, Japan, assignors to Fuji Keiki Kabushiki Kaisha, a corporation of Japan Filed June 11, 1965, Ser. No. 463,269 Claims priority, application Japan, June 16, 1964, 39/134,361; July 15, 1964, 39/40,615; July 27, 1964, 39/42,732

Int. Cl. D0111 7/40 US. Cl. 57157 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to processes for producing i crimped yarns at a high efficiency of thermoplastic synthetic yarns with a false twisting device.

It is known to obtain crimped yarns by twisting thermoplastic yarns, setting the twists and then untwisting the yarns.

The speed of the twisting head of such false twisting device has been made very high by the invention of a frictional type twisting process and the remarkable progress of the spindle driving method. But the progress of the heat setting process which is one of the most important elements of the false twisting device has not accompanied the twisting. Therefore, the working speed of the false twisting device has not been elevated to be high enough today.

It is an indispensable requirement for perfectly heatsetting thermoplastic synthetic yarns to fully and uniformly carry out the two requirements of heating and cooling. However, heating only has been considered but cooling has not been well considered. That is to say, the yarn heated with a heater is cooled only by being passed through air. In order to increase the cooling effect, it is usual to merely increase the length of the contact of the yarn with air. It is said that, in the case of such cooling with air as is mentioned above, the length of the cooling section should be more than 50% of that of the heating section. However, if the cooling section is merely made longer, the mechanical dimensions will become too large, the cost will rise and the difficulty of the operation will increase. Therefore, it is not desirable to merely make the cooling section longer. Further, the heated yarn can not be quickly cooled.

The first object of the present invention is to increase the cooling eifect without increasing the length of the cooling section.

It is also known that steam-setting is more effective than dry heat-setting in setting thermoplastic synthetic yarns. However, as there has been no proper steamsetting process in the false twisting device, the dry heatsetting process has ben adopted mostly.

The second object of the present invention is to carry out steam-setting.

Further, the third object of the present invention is to increase the coeificient of friction of a thermoplastic yarn being twisted by washing off any oil agent by adding 3,434,277 Patented Mar. 25, 1969 a small amount of water or a liquid composed mostly of water to the yarn.

The other objects of the present invention will become clear from the following explanation and drawings.

The-present invention is a process for producing false twisted crimped yarns of a high quality by heating a thermoplastic synthetic fiber yarn Well with a heatsetting heater in a false twisting device, bringing the heated yarn into contact with water or a liquid. composed mostly of Water between the heat-setting heater and a twisting head, removing excess water by such separating method as by the centrifugal force of the rotating yarn and allowing time to evaporate deposited water with the heat kept by the yarn so that the above mentioned objects may be attained within a short time.

That is to say, the yarn having passed through the heat setting heater will have been heated to such high temperature as about C. in the case of a polycapramide yarn. Therefore, as soon as the liquid is deposited on the yarn, it will be highly heated and vaporized to diffuse and will uniformly penetrate into the filament bundles of the yarn and the yarn will be uniformly steam-set.

In the conventional false twisting device, as synthetic fibers are inherently nonconductors for heat, when the yarn quickly passed through the heater, it will be well heated only on the surface but will be cooled due to the clearances between the filament bundles forming the yarn before heat is well transmitted to the core of the yarn. Therefore, the yarn will not be set well and will come to have a residual contraction. Thus there will be various defects in using the yarn.

On the other hand, in the process according to the present invention, the temperature of the surface of the yarn on which a very small amount of the liquid is deposited will be reduced but the liquid will be highly heated and vaporized and will penetrate into the filament bundles to lightly steam-set them. Therefore, a higher setting eifect than in the case of the conventional dry heatsetting will be obtained.

Further, the present invention is to also provide a process of elevating the coeflicient of friction of a yarn in the twisting head by washing off any oil agent by bringing the yarn into contact with water or a liquid composed mostly of water between the heat-setting heater and the twisting head.

The present invention shall be detailed in the following with reference to the drawings. In the drawings, the same parts are represented respectively by the same corresponding numerals.

FIGURES 1, 2 and 3 are explanatory views of false twisting devices embodying the present invention.

FIGURE 4 is a graph showing the results of experiments.

In FIGURE 1, 1 is a material yarn bobbin on which a thermoplastic yarn is wound, 2 is a feed roller and 3 is a heater, 4 is a frictional type false twisting device. 5 is a take-up roller (delivery roller). 6 is a traverse drum for winding traverses. 7 is a bobbin on which a crimped yarn is wound. 8 is a tank containing water or a liquid composed mostly of water. 9 is a cock for adjusting the amount of water. 10 is a jetting port. 11 is a suction port for the liquid and air. 12 is a suction pump. 13 is a drain pipe. Y is a yarn. The yarn Y coming out of the yarn bobbin 1 will be fed in with the feed roller 2 and will be twisted with the twisting head 4 while being heated with the heater 3. At the same time, the yarn Y will be cooled by water coming out through the jetting port 10. However, the time of contact with water is so short that the yarn Y will be cooled on the surface but will not be completely cooled in the core.

Further, the excess water deposited on the yarn Y will drop due to the gravity, will be separated by the centrifugal force of the yarn and will be carried away by an air current passing by the yarn and sucked into the suction port 11.

The water remaining in the yarn Y will be also vaporized by the heat kept by the yarn, will elevate the cooling effect and will lightly steam-set the yarn.

Further, the excess water coming out through the jetting port 10, the water separated by the centrifugal force of the yarn and the vapor evaporated by the heat of the yarn will be sucked together with the surrounding air by the pump 12 through the suction port 11 and will be drained out through the drain pipe 13.

The crimped yarn which has been twisted, heat-set and untwisted will be wound up on the winding bobbin 7 through the take-up roller and traverse drum 6.

FIGURE 2 shows an improvement of the apparatus shown in FIGURE 1 wherein, in the case of crimping a thick yarn, the excess water deposited on the yarn will be prevented from spreading as splashes and wetting the surroundings.

It is the same as in FIGURE 1 that, in FIGURE 2, 1 is yarn bobbin, 2 is a feed roller, 3 is a heater, 4 is a twisting head, 5 is a take-up roller, 6 is a traverse drum and 7 is a winding bobbin. 3' is a preheater. 14 is a feed water roll. 15 is a tank containing water or a liquid composed mostly of water.

The yarn Y coming out of the yarn bobbin 1 will be fed in by the feed roller 2 and will be twisted by the twisting head 4 while being heated by the preheater 3 and heater 3. At the same time, the yarn will come into contact with the liquid deposited on the roll 14 and will be cooled and lightly steamed. In order that it may be easy for the yarn to come into contact with the liquid in such case, it is preferable to make a shallow groove on the surface of the roll to be in contact with the yarn.

In case the excess liquid is deposited on the yarn, it will be separated by the centrifugal force by twisting and will make splashes. But, in this case, a cover or such suction device as in FIGURE 1 may be fitted.

However, if a method of preventing the liquid from spreading by adjusting the amount of the deposited liquid by varying the rotating speed of the roll is adopted, it will be convenient to the operation of the machine. The crimped yarn which has been twisted heat-set and untwisted will be wound up on the winding bobbin 7 through the take-up roller 5 and traverse drum 6.

Further, in depositing the liquid on the yarn, if the direction of the rotation of the roll is made reverse to the direction of the running of the yarn on the side of the roll in contact with the yarn, a better result will be obtained. In case it is difficult for the liquid to be deposited on the roll or yarn, a surface active agent or the like may be added to the liquid.

FIGURE 3 shows a part of the false twisting device of the present invention wherein the yarn feeder and take-up device are the same as in FIGURES 1 and 2 and are therefore omitted in the drawing. The yarn Y heated through the heater 3 will come into contact with the roll 14 while being twisted by the twisting head 4, will have water or a liquid composed mostly of water deposited on it, will be cooled and lightly steam-set and will be wound up through the take-up roller 5. The lower part of the roll 14 is dipped in the water or the liquid composed mostly of water in such semicylindrical tank 15 as is illustrated. Said liquid will be fed from a tank 17 through a pipe by having the amount adjusted with a cock 18.

As a thermoplastic synthetic yarn is crimped as described above, there can be obtained various effects that the distance between the heater and twisting head can be made shorter than in the case of only air-cooling the yarn and that the yarn can be steam-set.

4 The present invention shall be explained with reference to the following concrete examples:

Example 1 An example wherein a polycapramide fiber yarn (which shall be known as a nylon yarn hereinafter) of 30 d./ 10 fil. was crimped with the false twisting device in FIG- URE 1 shall be explained.

First of all, the yarn contact length of the setting part of the heat-setting heater 3 was made 420 mm. The temperature of its central part was made C. The distance from the end of the setting part to the first yarn contact point of the twisting part was made 295 mm. The distance (which shall be known as an air-cooling section hereinafter) from the end of the setting part to the point of contact of the nylon yarn with water (which point shall be known as a water contact point hereinafter) was made 50 mm. The yarn speed ratio (which is known also as a specific sliding and is the yarn speed/surface speed of the frictional type false twisting head) was made 0.22. The amount of water was made 1.2 liters per minute. The crimping speed of the yarn was varied. The relation with the quality of the yarn (which may be considered the relation between the heating time with the heat-setting heater and the quality of the yarn as the other conditions were the same) was determined by experiments. As a result, it was found that, in case the heating time was longer than 0.15 to 0.17 second, there was substantially no difference from the quality of a yarn crimped with a spindle type false twisting device. (This yarn shall be known as a contrast yarn hereinafter and was crimped at a number of revolutions of the spindle of 9500 rpm, a length of the heater of 420 mm. and a yarn speed of 18.5 m./min.) In such case, when the yarn was not brought into contact with water, its limit was 0.16 to 0.19 second. Therefore, after all, by the increase of the cooling effect and the steam-setting effect, the heat-treating effect improved by about 10%.

Then the heating time was made longer than 0.2 second. While the other conditions were kept constant, the distance (which shall be known as a wet-cooling section hereinafter) from the water contact point to the first yarn contact point of the twisting head was adjusted and the yarn speed was varied to vary the time of the passage of the yarn through the wet-cooling section (which time shall be known as a wet-cooling time hereinafter). Then, in case said time was longer than 0.012 to 0.014 second, the quality of the crimped yarn was not inferior to that of the contrast yarn. When the time was shorter than that, the twisting tended to become unstable presumably because the amount of evaporation of water was so small that the yarn was too wet. Further, when the heating time was made longer than 0.2 second, the wet-cooling time was made longer than 0.015 second and the other conditions were kept constant but the time of the Passage through the air-cooling section (which time shall be known as an air-cooling time hereinafter) was varied, it was found that the air-cooling time had better be as short as possible and that, in case the air-cooling time was less than 15% of the heating time, the process of the present invention was very effective. However, when the air-cooling time exceeded 30 to 40% of the heating time, the effect was reduced remarkably. Specifically, when it exceeded 50 to 60%, even if the yarn was brought into contact with water, no significant difference was seen.

Example 2 In case a nylon yarn of 50 d./ 17 fil. was crimped by substantially the same process as in Example 1, it was found that the heating time must be longer than 0.2 to 0.24 second and that the wet-cooling time must not be shorter than 0.015 to 0.017 second. Further, there was obtained a result that the relation between the air-cooling time and heating time was not so different from that in Example 1.

Example 3 An example wherein a nylon yarn of 70 d./34 fil. was crimped with the same false twisting device as in Example 1 shall be explained. The yarn contact length of the setting part was made 620 mm., the temperature of the central part of the set part was made 180 C., the temperature distribution in the direction of the length was made +1 C. to 4 C. in the setting part except 100 mm. from each end, the yarn speed ratio was made 0.23 and the amount of water was made 1.2 liters/ min. in carrying out the experiment. The contrast yarn was crimped at a yarn speed of 28 m./min. in a spindle type false twisting device in which the heater length was 420 mm. and the number of revolutions of the spindle was 95,000 r.p.m.

First of all, when the air cooling section was made 10 mm. long, the wet-cooling section was made about 280 mm. long and the minimum value of the heating time was determined, there was obtained a result that it was 0.25 to 0.3 second. This was a value more than 10% smaller than in the case of using no water.

Then, when the air-cooling section was made 10 mm. long, the heating time was made longer than 0.3 second and the minimum value of the wet-cooling time was determined, it was concluded that the wet-cooling time must be longer than 0.018 to 0.02 second.

Further, when the heating time was made longer than 0.3 second, the wet-cooling time was made longer than 0.02 second and the relation between the heating time and air-cooling time was investigated, the result was substantially the same as in each of the preceding examples.

Example 4 An example wherein a nylon yarn of 110 d./ 24 fil. was crimped with a false twisting device of such structure as in FIGURE 2 shall be explained.

The length of the setting part of the preheater 3 was made 250 mm. (as the yarn was turned and was again brought into contact, the yarn contact length was 500 mm), the temperature of the central part of the preheater was made 170 C., the temperature distribution in the direction of the length was made C. to 5 C. (except 40 mm. from each end), the yarn contact length of the heat-setting heater 3 was made 620 mm. (contact with the entire length of 620 mm. of the setting part), the temperature of the central part of the heater 3 was made 185 C., the temperature distribution in the direction of the length (except 100 mm, from each end) was made +1 C. to -4 C., the distance between the ending end of the preheater 3' and the beginning end of the heat-setting heater 3 was made 35 mm., the material of the feed water roll 14 was made a phenol resin, the diameter of the roll was made 45 mm., the number of revolutions of the roll was made 105 rpm. and the yarn speed ratio was made 0.21 in carrying out the experiment.

The contrast yarn was crimped at a yarn speed of 26 m./min. in a spindle type false twisting device in which the heater length was 420 mm. and the number of revolutions of the spindle was 80,000 rpm.

First of all, when the air-cooling section was made 55 mm. long, the wet-cooling section was made about 250 mm. long and the minimum value of the heating time was determined, it was found that the value must be 0.4 to 0.45 second. This heating time was substantially the same as in the case that the yarn was heated with a continuous heater of a yarn contact length of 1100 mm. and was not brought into contact with water. It was because the temperature of the preheater was somewhat lower and, between the preheater and heat-setting heater, there was a place in which the yarn passed through air though for a short distance. It is considered that, in case such place continues at the same temperature, it will be possible to reduce the heating time to about 0.35 to 0.4 second. When the air-cooling section was made 55 mm., the heating time was made longer than 0.5 second and the minimum value of the wet-cooling time was determined, there was obtained a result that it was 0.022 to 0.025 second. Further, when the heating time was made longer than 0.5 second, the wet-cooling time was made longer than 0.03 second and the ratio of the heating time to the air-cooling time was investigated, it was found that, in case the air-cooling time was less than about 10% of the heating time, the process of the present invention was very effective, that, when it exceeded 25 to 35%, the effect reduced very much and that, when it exceeded 40 to 50%, there was no specific elfect as compared with the case of air-cooling only. The difierence of this ratio from those in Examples 1 to 3 can be presumed to be because, as described in the case of the explanation of the heating time, the preheating temperature was low and, as there was a place in which the yarn came into contact with air between the preheater and heat-setting heater, the heating elfect was low for the heating time. Therefore, it is considered that there may be substantially no great difference from those in Examples 1 to 3.

Example 5 When a nylon yarn of 210 d./34 fil. was crimped in the same manner as in Example 4, there were obtained results that the minimum heating time was 0.6 to 0.7 second, the minimum wet-cooling time was 0.03 to 0.035 second and the ratio of the heating time to the air-cooling time was the same as in Example 4.

Example 6 It was so difficult to crimp a yarn of more than 250 deniers with the frictional type false twisting head that the twisting head 4 in FIGURE 2 was replaced with a spindle. The other conditions than in the twisting part were made the same as in Example 4 and a nylon yarn of 420 d./48 fil. was crimped. In such case, the minimum heating time was 1.0 to 1.2 seconds, the minimum wetcooling time was 0.045 and 0.05 second and the ratio of the heating time to the air-cooling time approximated that in Example 4.

Example 7 In the case of a nylon yarn of 840 d./ 136 fil., the minimum heating time was 1.7 to 2.0 seconds, the minimum wet-cooling time was 0.06 to 0.07 second and the ratio of the heating time to the air-cooling time was not so different from that in each of the preceding examples.

'Example 8 When a nylon yarn of about 1500 d./ fil. was made by doubling 7 nylon yarns of 210 d./15 fil. and was crimped, there were obtained results that the minimum heating time was 3.0 to 3.5 seconds, the minimum wetcooling time was 0.09- to 0.1 second and the ratio of the heating time to the air-cooling time was not so different from that in Example 4 but fluctuated considerably.

Example 9 An example wherein a nylon yarn of 20 deniers was crimped with the false twisting device in FIGURE 3 shall be explained. In case roll 14 was not used and the yarn was crimped with only the heater 3, the number of twists was 3100 t./m. In case water was added "to the yarn with the roll 14, the number of twists was 3240 t./m. Thus the increase of the number of twists was seen. Further, in case active agents were added to the solvent, the results were as follows:

TABLE 1 Additives Number of Efiects twists (t./m.)

Anionic active agent, 0.1% 3, 250 Softened. Cationic active agent, 0.1% 3,100 Do. Neutral active agent 0.1 3,160 Do. Brilliant blue 6B, 6 3, 650 Not changed. Orange II, 5 3, 360 Do. Colloidal silica, 5% 4,030 Stifiened.

unifor mly penetrate into the yarn to prevent the fluctuation of the number of twists.

What we claim is:

1. A process for producing crimped yarns by crimping thermoplastic synthetic yarns with a false twisting device comprising heating a yarn for more than .0125 D-' second (wherein D is a number of deniers), bringing said yarn into contact with a liquid for a time less than 60% of the heating time without interrupting the twist running so that a proper amount of the liquid may be deposited on the yarn, leaving the yarn for a wet-cooling time of more than .002 D second (wherein D is a number of deniers) and then making the yarn reach a twisting part.

2. The process according to claim 1 wherein said thermoplastic synthetic fiber yarns are polycapramide yarns, polyhexamethylene adipamide yarns, polyethylene terephthalate yarns, polypropylene yarns and yarns of their copolymers.

3. The process according to claim 1 wherein said liquid is water or a liquid composed mostly of Water with the addition of a solvent, surface active agent or colloidal silica.

4. The process according to claim 1 wherein said liquid is deposited on the yarn by bringing the yarn into contact with a rotary roll rotating as dipped partly in the liquid.

5. The process according to claim 1 wherein said liquid is deposited on the yarn by jetting or dropping the liquid.

6. The process according to claim 1 wherein the twisting head is preferably a frictional type high speed false twisting device.

7. The process according to claim 1 wherein the excess liquid spread as splashes by the centrifugal force and the generated vapor are removed by suction.

References Cited UNITED STATES PATENTS 2,477,909 8/ 1949 Stockly 5734 3,077,724 2/1963 Stoddard et a1 5734 3,237,392 3/1966 Crouzet 57l57 3,333,409 8/1967 Servage 57l57 DONALD E. WATKINS, Primary Examiner. 

